Do not assume a pressure method suitable for an ordinary sink is suitable for every disposer installation. Consult the model guidance and have an uncertain blockage assessed before forcing water through connected components.
What the observation tells you
The sink may share hoses, overflow routes and other fittings that change where pressure goes. Chemical liquid previously added makes any splashing particularly concerning. Keep the motor off and do not combine motor operation with plunging or a pressure jet.
A useful next step
Explain the drainage symptoms and any treatment already attempted to the person clearing the blockage. Leave dismantling and unapproved pressure methods to an appropriate professional assessment.
Manuals and supporting guidance
Model-specific instructions take priority. These references support the practical principles discussed here; they do not diagnose your appliance.