watching him and he continues to ask us to call kevin, this dallas police officer. so we actually get ahold of kevin and kevin doesn't know mr. wallace. only knows that he's had his number and he's called him so many times, it's almost to ah-hah rasing point. >> the negotiators tell wallace that they are unable to reach kevin and offer him a chair to sit down. >> it was a tactical advantage for us because we knew we had his movement restricted. if we have to shoot mr. wallace the child won't fall from six foot level of height but smaller level. >> zoe is remarkably calm but wallace is deteriorating by the minute. >> he's sweating profusely, agitated and irritated. david, who's trained in crisis intervention knows that mr. wallace is having a manic episode. he's trying to calm him down. >> but after more than 30 minutes of negotiations, wallace still isn't cooperating. instead, he begins counting down.