Putze, in his role as senior national officer in command of the contingent, needed to "maintain an environment where you're prepared to put people under your command in harm's way for the success of the mission".
Boswell said the operation - maintaining stability at the border of Israel and Egypt - was "without question" risky and dangerous.
A commander engaging in inappropriate behaviour with a subordinate undermined the trust and authority needed for someone in that position.
Putze has pleaded not guilty to four charges and one alternative charge, including failing to comply with written orders by entering into a relationship with a member of his contingent, failing to report the relationship, and lying to a superior about the alleged relationship.
He is also accused of engaging in a public display of affection while in a service environment by sharing "intimate embraces" with Captain Carolyne Cappola.
Prosecutor Flight Lieutenant Nina White said Putze characterised his involvement with Cappola as a "one-night stand" and did not accept he had entered into a relationship.
Boswell, who was a brigadier at the time Putze returned from deployment, said he clearly remembered talking to Putze about rumours he'd engaged in inappropriate behaviour with a person in his contingent.
"I can't remember if I raised it or if Lieutenant Colonel Putze raised it, but the topic of the allegations was discussed . . . [he] quite clearly said to me that nothing of an inappropriate nature or a sexual nature had occurred."
Putze told him the "intimate embraces" he was accused of sharing with a member of his contingent were "purely as a result of him needing to comfort that member of the contingent", he said.
At that time he had not mentioned the person he comforted was Cappola.
Defence counsel Commander Christopher Griggs asked Boswell if he remembered making a comment to Putze that he knew how to "throw a grenade in the duck pond". Boswell said he did not remember such a comment, but in context it would have been a "flippant comment in a glib manner" before entering the official debrief.
Cappola has also given evidence in the court martial this morning, saying Putze would regularly check in on her during deployment and became a person she could confide in after her husband told her he wanted to divorce.
Then after drinking with a group at Putze's accommodations, she stayed to help clean up and ended up having sex with him, she said.
Cappola described it as a "lapse in judgment" and said they both agreed it shouldn't continue. At the end of their deployment Cappola was feeling emotional and burst into tears more than once at a group gathering, and said Putze hugged her twice.
However, the pair pursued the relationship after deployment had ended, and are now engaged, she told the court.
Captain Catherine Hayward also gave evidence saying she saw the pair kiss at a bar in Dubai, and that at one time she believes she saw a WhatsApp message on Cappola's phone from Putze saying "I can't wait to hold you later".
The court martial in Trentham, Upper Hutt, will continue through the week.
