And the Mexicans knew it, too.

The shrill screaming of the women began again from the flat roofs of the houses, and shouts burst from the army also.
"We have them! We have them!" cried Santa Anna, exultant and excited.
Sheets of flame still burst from the Alamo, and the rifles still poured bullets on the swarming Mexican forces, but the breach had been made.
The Mexicans went over the low wall in an unbroken stream, and they crowded through the sallyport by hundreds.

They were inside now, rushing with the overwhelming weight of twenty to one upon the little garrison.
They seized the Texan guns, cutting down the gunners with lances and sabers, and they turned the captured cannon upon the defenders.
Some of the buildings inside the walls were of adobe, and they were soon shattered by the cannon balls.

The Texans, covered with smoke and dust and the sweat of battle, were forced back by the press of numbers into the convent yard, and then into the church and hospital.

Here the cannon and rifles in hundreds were turned upon them, but they still fought.
Often, with no time to reload their rifles, they clubbed them, and drove back the Mexican rush.
The Alamo was a huge volcano of fire and smoke, of shouting and death.
Those who looked on became silent again, appalled at the sights and sounds.