Why do fighters fly vertically upward after being locked by missiles?

The seeker of the previous infrared guided missile is not very advanced, and it is impossible to distinguish the heat source of the engine tail nozzle from other heat sources. Once the fighter is locked, it can use other heat sources to get rid of missile tracking, such as flying to the sun. General air-to-air missiles are heat-seeking missiles, which attack the target by tracking the huge heat energy of the tail nozzle of the aircraft engine. When the aircraft is locked by this missile, it can only release the high-heat jamming bomb and make a big overload maneuver at the same time to avoid the missile's tracking. Jamming bombs sometimes can't fool missiles, and they can only find the strongest heat source in the sky, only the sun. So once the plane is locked by a missile, it will fly directly to the sun regardless. When the missile catches up, it will suddenly collect oil and do overload maneuver. The missile will look for the strongest radiation source, and the sun will fly until the energy is exhausted and self-destructed. This kind of escape is only suitable for daytime and rainy days, because fighters escape at supersonic speed and can see the sun through the clouds in a few seconds. In air combat, if your fighter plane is locked by an air-to-air missile launched by an enemy fighter plane or an air defense missile launched by an enemy air defense force, the missile warning instrument in the cockpit of the fighter plane will prompt the pilot that there is an incoming missile. At this time, the pilot's main task is to maneuver the fighter plane, and at the same time, he will launch a large number of infrared trailing decoys and metal chaffs to jam the radar, so as to get rid of the pursuit of air-to-air missiles and air defense missiles. After the pilot is locked by enemy air-to-air missiles and air defense missiles, he will generally do a maneuver to get rid of it, that is, turn on the afterburner and climb vertically. After that, the war machine will do all kinds of maneuvers, such as somersault, diagonal somersault, tumbling, figure-eight hovering and so on. Usually, if it is used with infrared trailing bait and jamming metal chaff, it can deal with most infrared guided or radar guided air-to-air missiles and air defense missiles.