Officer Johnny Alvarez pulled up to the horrific scene Wednesday, moments after a maroon pickup crossed over the westbound lanes of the Grand Parkway into oncoming traffic.
"The best way I can describe it, mass chaos -- a huge field of debris," Alvarez said.
Investigators said 54-year-old Charles Glaze was driving the pickup.
Alvarez saw that Glaze needed help, and because he always kept an extensive medical kit in his personal car, he had exactly what he needed to wrap Glaze's head and treat other people before paramedics arrived.
Alvarez said he saw the truck was overturned. He said he got on his knees and went through the rear passenger window.
"A lot of people might say it's heroic. In all honesty, I see it as my instinct reaction. Having served in the military, it's the right thing to do. As a law enforcement officer, we took an oath, whether you're on or off duty, in your jurisdiction or not, we always try to preserve life and assist in any shape or form. It's a clock that never turns off," Alvarez said.
Glaze and four other people were taken to Memorial Hermann Hospital in The Woodlands. As of late Wednesday, one of those people was still in critical condition.
Michael Brown was one of the victims who was killed. He was driving a Chevy.
Meanwhile, Glaze has not been charged with anything. Deputies said Glaze did not appear to be intoxicated and said he is cooperating with their investigation. He told authorities that he doesn't remember what happened before the accident.
Glaze apparently has a history of seizures, according to the sheriff's office. It was not immediately known if Glaze was cleared by a doctor to drive.
SEE ALSO: Charles Glaze arrested in connection with attempted kidnapping at cemetery
According to sources, not only does Glaze have a medical history but he also has a criminal history, as he was charged in 2017 with aggravated kidnapping and assault out of Montgomery County.
Investigators say in 2017 a woman was visiting her son's gravesite when Glaze attacked her at the Klein Memorial Cemetery in Tomball.
Deputies say he assaulted her with a Taser and showed her a gun before tying her up with zip ties and a necktie. Deputies say she managed to escape.
In another incident, deputies with the Montgomery County Sheriff's Office say a man matching Glaze's description reportedly made another woman feel uncomfortable at a different Klein cemetery and she reported that to authorities.