Derek Fisher peeked over his shoulder, sized up his target, and threw a vicious shoulder block that leveled Luis Scola.

And Fisher is regarded as one of the NBA’s good guys.

So is Dwight Howard, who also was suspended a game in this postseason for taking a shot at an opponent’s head.

If guys like them can’t keep their cool in the playoffs, who can?

“When our players are in a competitive environment with the stakes being extremely high, I’ve always felt that it brings out the best and the worst in people, be it players, be it coaches,” NBA executive vice president of operations Stu Jackson said.

“And sometimes even the players that wouldn’t ordinarily behave in a manner during the regular season, during the postseason it changes, and sometimes players do things that they probably later regret.”

Jackson already has handed out three suspensions, one more than all of last postseason. Besides Fisher and Howard, he also penalized Orlando’s Rafer Alston a game for slapping Boston guard Eddie House in the head.

None fit the profile of a head hunter, yet nobody seems too shocked when even the good citizens suddenly have bad intentions.

“It doesn’t surprise me,” Denver’s Chauncey Billups said. “Playoff time is a lot more chippy. Everything means a lot more so you’re going to do everything you can to help your team out.”

Sometimes it ends up hurting. Orlando won both games without its suspended players, and the Lakers survived without Fisher, but the Dallas Mavericks lost Game 6 of the 2006 Western Conference semifinals without Jason Terry, who was suspended after throwing a punch at San Antonio’s Michael Finley in the previous game.

“It was me three years ago. I lose my cool and cost my team a game,” Terry said. “You know that it’s the heat of the battle, but at the same time you’ve got to be realistic. You don’t want to hurt your team and be suspended.

“We got out of the situation good, but it easily could’ve been a real downward spiral for us. We could’ve lost Game 7.”

Still, players sometimes find it hard not to react, even ones on title contenders who have every reason to walk away.

“Absolutely, we have a few guys on this team who could lose their cool,” said NBA MVP LeBron James of Cleveland. “I’m not going to say who. Hopefully guys on our team know how important the game is and try not to take things personal. But there comes a time where someone can really test your manhood.”