Yep, sounds like Twiggs put up a real fight.
On the other hand he could have been better prepared than he was and put his troops on alert and in better defensive positions. The San Antonio newspaper a day or two before the Texas troops arrived warned that thousands of Texas troops were coming. It turned out to be only 800, but they far outnumbered the 160 Federal troops in town.
Twiggs could have refused to surrender Federal facilities in Texas. In he had done that, the facilities would be taken by force anyway with heavy casualties in his troops. He was in a hopeless position.
I don't think Robert E. Lee thought very highly of Twiggs action.
Apparently the Federal troops were ordered the night before the Texas troops came not to load their weapons or resist any large organized force attempting to take the facilities by force. To do so, IMO, might well have started the war and been the end of those Federal troops as well as the loss of all of their arms.
The Feds were aware that the armed force of Texans was coming. They appear to have had a better estimate (at least from the post-incident Federal correspondence) of the number of troops coming to San Antonio than the local newspaper had published the day before.
The Federal troops were awakened when the Texas troops started coming into the city at 4 AM. The Federal troops assembled and were told to stay in their quarters. A later report by their local officer noted that none of them could move without having several hundred guns pointed at them.
Twiggs negotiated that the Federal troops could take two batteries of light artillery with them, artillery that would have otherwise gone to the state whether Twiggs had chosen to fight or just acceded to the initial demand of the state.