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During the 49ers' dominating 30-12 win over the Giants on Thursday night, things got kind of heated near the end of the first half. 

With just 13 seconds lef to play in the second quarter, Brock Purdy took a knee that should have ended the half, but it didn't because 49ers left tackle Trent Williams got into it with New York's A'Shawn Robinson

Right after the play, Williams pushed Robinson and that's when things got a little crazy. After Robinson responded by getting in Williams' face, the 49ers star appeared to retaliate by taking a swing at Robinson

After the scuffle, both players were penalized and Purdy had to take another knee to end the half. 

A punch to the face usually leads to an ejection in the NFL, but it didn't in this case. If Williams would have been ejected, it would have been a brutal loss for a 49ers team that was only leading 17-6 at the half. 

So why didn't Williams get ejected? 

Walt Anderson, the NFL Senior's Vice President of Officiating, attempted to answer that question during an interview with a pool reporter after the game. 

"We ended up looking at the video we had available to us, and we just didn't see anything that rose to the level of flagrant, which is the standard that we have to apply to disqualify the player," Anderson said of why Williams got to stay in the game. 

At that point, the pool reporter pointed out that Williams had struck another player in the facemask, something that usually leads to an ejection. 

"These are judgment calls and a lot of times you might end up having an open hand, often a stiff arm to the face, versus a closed fist punch, which certainly carries a different weight to it," Anderson said. "So, we ended up looking at the available video we had and just didn't feel like the actions rose to the level of flagrant. You can certainly end up having contact with hands to the helmet, and some of those actions would be deemed a punch, others would not."

Although the video appeared to show Williams throwing a punch with a closed fist, the officiating crew apparently did not feel the same way. 

"We couldn't confirm that 100 percent from the standpoint of was it truly a closed fist with a strike, we just couldn't determine that," Anderson said. 

Due to that fact, the officiating crew decided not to eject Williams. The 49ers left tackle had a solid night in a game where San Francisco piled up 441 yards of total offense.