A desperate cry for help bursts forth from a feeling of drowning and losing control, capturing a moment when danger reaches its absolute peak and threatens a person's very existence.
The primary approach among commentators is that this imagery of water is not literal. Instead, it serves as a powerful metaphor for enemies, severe hardships, and deep troubles that wash over a person [אבן עזרא, מאירי, מצודת דוד]. More specifically, the rising floodwaters symbolize the various nations of the world that have oppressed the Israelites throughout history [רש״י]. The severity of the situation is compared to a sudden flood that has risen all the way to a person's neck. With the water blocking their breathing passage, they are on the brink of drowning, their life force ready to slip away [רד״ק, מצודת דוד, מאירי, ביאור שטיינזלץ, מלבי״ם].
However, others view this rising danger as a spiritual threat rather than a purely physical one. In this light, the imagery points to the exiles of the Israelites, particularly the Babylonian exile. While typical oppression damages the body through forced labor, the harsh decrees in Babylon, such as the command to bow to idols, struck at a much deeper level. It was a crisis that damaged faith and threatened to destroy the soul itself [אלשיך].
Alongside these metaphorical explanations, a historical tradition links this desperate cry to a literal event of extreme self-sacrifice at the Red Sea. According to this account, the plea is the personal voice of Nachshon ben Aminadav. As the tribes of Israel stood on the shore arguing over who would enter the sea first, Nachshon leaped into the crashing waves. He began to sink until the water reached his very breath. At that moment, Moses was extending his prayers, until God instructed him to stop praying and take action because His friends were drowning in the sea. Because Nachshon willingly jumped into the water and risked his life, his tribe, the tribe of Judah, was rewarded with the kingship over the Israelites [תורה תמימה].