The man is desperate to save himself from nomination (and who can blame him). Yes, he's spent a lot of time trying to talk Keesha out of putting Angie on the block, but he's seen that's impossible. After the food competition, he made his way back up to HOH, and informed her that Angie had said she would have nominated April and Libra if she had won HOH. Keesha agreed, though, that it makes sense that she would go after the women that were going after her.
After more meaningless chitchat, Keesha just told him she won't nominate him if he would promise not to use the POV to save her. He quickly agreed. A few minutes later, she asked if he would vote to evict her. The answer is yes because he "doesn't want to pull the trigger so early in the game".